Mechanical Engineering Department, Maroun Semaan Faculty of Engineering and Architecture, American University of Beirut, Bliss Street, PO. Box 11-0236, Beirut, Lebanon.
Center for the Study of Tobacco Products, Virginia Commonwealth University, 821 West Franklin Street, Richmond, VA, 23284, USA.
Sci Rep. 2020 Oct 1;10(1):16263. doi: 10.1038/s41598-020-73385-6.
Nicotine in electronic cigarette (ECIG) liquids can exist in a free-base or protonated (or "salt") form. Protonated nicotine is less aversive upon inhalation than free-base nicotine, and many ECIG manufacturers have begun marketing protonated nicotine products, often with high nicotine concentrations. Regulations intended to control ECIG nicotine delivery limit nicotine concentration but do not consider nicotine form. In this study, we systematically examined the effect of nicotine form on nicotine yield for varying powers and liquid vehicles. A Kanger Subox Mini-C tank ECIG (0.5 Ω) was used to generate aerosols at varying powers (5-45 W) from liquid solutions that contained either free-base or protonated nicotine at 15 mg/g concentration, with a liquid vehicle consisting of either propylene glycol (PG) or vegetable glycerin (VG), resulting in four different solutions (free-base/PG, free-base/VG, protonated/PG, and protonated/VG). Nicotine yield was quantified using gas chromatography-mass spectrometry. Nicotine yields were not influenced by nicotine form under any condition investigated. At each power level, PG-based liquids resulted in approximately double the nicotine yield of VG-based liquids. Nicotine concentrations in the aerosols matched those of the parent liquids for both the PG and VG conditions. Increasing power led to greater nicotine yield across all conditions. The amount of nicotine emitted by an ECIG is independent of whether the nicotine is free-base or protonated, however the liquid vehicle has a strong effect on yield. Regulations intended to limit nicotine emissions must consider not only nicotine concentration, but also liquid vehicle and device power.
电子烟（ECIG）液体中的尼古丁可以以游离碱或质子化（或“盐”）形式存在。质子化尼古丁在吸入时比游离碱尼古丁的刺激性小，许多 ECIG 制造商已经开始销售质子化尼古丁产品，通常具有高尼古丁浓度。旨在控制 ECIG 尼古丁输送的法规限制了尼古丁浓度，但不考虑尼古丁形式。在这项研究中，我们系统地检查了尼古丁形式对不同功率和液体载体的尼古丁产率的影响。使用 Kanger Subox Mini-C 罐 ECIG（0.5 Ω）在 5-45 W 的不同功率下从含有 15 mg/g 浓度的游离碱或质子化尼古丁的液体溶液中产生气溶胶，液体载体由丙二醇（PG）或蔬菜甘油（VG）组成，导致四种不同的溶液（游离碱/PG、游离碱/VG、质子化/PG 和质子化/VG）。使用气相色谱-质谱法定量尼古丁产量。在任何研究条件下，尼古丁形式都不会影响尼古丁产率。在每个功率水平下，基于 PG 的液体产生的尼古丁产量约为基于 VG 的液体的两倍。对于 PG 和 VG 条件，气溶胶中的尼古丁浓度与母体液体中的尼古丁浓度相匹配。增加功率会导致所有条件下的尼古丁产率增加。ECIG 释放的尼古丁量与尼古丁是游离碱还是质子化无关，但液体载体对产率有很大影响。旨在限制尼古丁排放的法规不仅必须考虑尼古丁浓度，还必须考虑液体载体和设备功率。
